U.S. patent number 6,137,500 [Application Number 09/112,797] was granted by the patent office on 2000-10-24 for utilizing of brush stroking techniques in the generation of computer images.
This patent grant is currently assigned to Silverbrook Research Pty Ltd. Invention is credited to Paul Lapstun, Kia Silverbrook.
United States Patent |
6,137,500 |
Silverbrook , et
al. |
October 24, 2000 |
Utilizing of brush stroking techniques in the generation of
computer images
Abstract
A form of "brushing" an computer graphic image is disclosed. The
method includes brushing a simulated brush stroke along a path in a
computer graphics image by converting the path to a series of
corresponding line segments; determining a current convex brush
edge of the path; determining a series of substantially equally
spaced points along the convex edge; determining corresponding
parametric points along the path; and utilising the parametric
points to place brush template structures in the computer graphics
image. In a first refinement, the opacity channel is combined such
that the maximum of a current brush template opacity value and a
current computer graphic image opacity channel value becomes the
new current computer graphic image opacity channel value. In a
second refinement, the opacity channel is combined such that the
minimum of a current brush template opacity value and a current
computer graphic image opacity channel value becomes the new
current computer graphic image opacity channel value. In a third
refinement, the computer graphic image further comprises a
footprint channel which is set when each pixel is composited and
the opacity channel is only composited with the computer graphic
image opacity channel when the footprint channel is not set.
Inventors: |
Silverbrook; Kia (Sydney,
AU), Lapstun; Paul (Sydney, AU) |
Assignee: |
Silverbrook Research Pty Ltd
(Balmain, AU)
|
Family
ID: |
3802790 |
Appl.
No.: |
09/112,797 |
Filed: |
July 10, 1998 |
Foreign Application Priority Data
Current U.S.
Class: |
345/442;
348/E5.055; 348/E5.024 |
Current CPC
Class: |
H04N
1/2154 (20130101); H04N 5/225 (20130101); G06F
21/86 (20130101); G06F 21/79 (20130101); H04N
1/2112 (20130101); H04N 5/2628 (20130101); G06F
2221/2129 (20130101); H04N 2101/00 (20130101) |
Current International
Class: |
G06F
21/00 (20060101); H04N 5/262 (20060101); H04N
5/225 (20060101); H04N 1/21 (20060101); G06F
015/00 () |
Field of
Search: |
;345/440,441,442,443,118,121 |
References Cited
[Referenced By]
U.S. Patent Documents
|
|
|
4455609 |
June 1984 |
Inamura et al. |
5247611 |
September 1993 |
Norden-Paul et al. |
6020898 |
February 2000 |
Saito et al. |
|
Primary Examiner: Nguyen; Phu
Parent Case Text
CROSS REFERENCES TO RELATED APPLICATIONS
The following co-pending US patent applications, identified by
their US patent application serial numbers (USSN), were filed
simultaneously to the present application on July 10, 1998, and are
hereby incorporated by cross-reference:
09/113,060; 09/113,070; 09/113,073; 09/112,748; 09/112,747;
09/112,776; 09/112,750; 09/112,746; 09/112,743; 09/112,742;
09/112,741; 09/112,740; 09/112,739; 09/113,053; 09/112,738;
09/113,067; 09/113,063; 09/113,069; 09/112,744; 09/113,058;
09/112,777; 09/113,224; 09/112,804; 09/112,805; 09/113,072;
09/112,785; 09/112,797; 09/112,796; 09/113,071; 09/112,824;
09/113,090; 09/112,823; 09/113,222; 09/112,786; 09/113,051;
09/112,782; 09/113,056; 09/113,059; 09/113,091; 09/112,753;
09/113,055; 09/113,057; 09/113,054; 09/112,752; 09/112,759;
09/112,757; 09/112,758; 09/113,107; 09/112,829; 09/112,792;
09/112,791; 09/112,790; 09/112,789; 09/112,788; 09/112,795;
09/112,749; 09/112,784; 09/112,783; 09/112,763; 09/112,762;
09/112,737; 09/112,761; 09/113,223; 09/112,781; 09/113,052;
09/112,834; 09/113,103; 09/113,101; 09/112,751; 09/112,787;
09/112,802; 09/112,803; 09/113,097; 09/113,099; 09/113,084;
09/113,066; 09/112,778; 09/112,779; 09/113,077; 09/113,061;
09/112,818; 09/112,816; 09/112,772; 09/112,819; 09/112,815;
09/113,096; 09/113,068; 09/113,095; 09/112,808; 09/112,809;
09/112,780; 09/113,083; 09/113,121; 09/113,122; 09/112,793;
09/112,794; 09/113,128; 09/113,127; 09/112,756; 09/112,755;
09/112,754; 09/112,811; 09/112,812; 09/112,813; 09/112,814;
09/112,764; 09/112,765; 09/112,767; 09/112,768; 09/112,807;
09/112,806; 09/112,820; 09/112,821; 09/112,822; 09/112,825;
09/112,826; 09/112,827; 09/112,828; 09/113,111; 09/113,108;
09/113,109; 09/113,123; 09/113,114; 09/113,115; 09/113,129;
09/113,124; 09/113,125; 09/113,126; 09/113,119; 09/113,120;
09/113,221; 09/113,116; 09/113,118; 09/113,117; 09/113,113;
09/113,130; 09/113,110; 09/113,112; 09/113,087; 09/113,074;
09/113,089; 09/113,088; 09/112,771; 09/112,769; 09/112,770;
09/112,817; 09/113,076; 09/112,798; 09/112,801; 09/112,800;
09/112,799; 09/113,098; 09/112,833; 09/112,832; 09/112,831;
09/112,830; 09/112,836; 09/112,835; 09/113,102; 09/113,106;
09/113,105; 09/113,104; 09/112,810; 09/112,766; 09/113,085;
09/113,086; 09/113,094; 09/112,760; 09/112,773; 09/112,774;
09/112,775; 09/112,745; 09/113,092; 09/113,100; 09/113,093;
09/113,062; 09/113,064; 09/113,082; 09/113,081; 09/113,080;
09/113,079; 09/113,065; 09/113,078; 09/113,075.
Claims
We claim:
1. A method of brushing a simulated brush stroke along a path in a
computer graphics image said method comprising the steps of:
converting the path to a series of corresponding line segments;
determining a current convex brush edge of said path;
determining a series of substantially equally spaced points along
said convex edge;
determining corresponding parametric points along said path;
and
utilising said parametric points to place brush template structures
in said computer graphics image.
2. A method as claimed in claim 1 wherein said brush template
structures includes an opacity channel which is combined with the
opacity channel of the computer graphic image.
3. A method as claimed in claim 2 wherein said opacity channel is
combined such that the maximum of a current brush template opacity
value and a current computer graphic image opacity channel value
becomes the new current computer graphic image opacity channel
value.
4. A method as claimed in claim 2 wherein said opacity channel is
combined such that the minimum of a current brush template opacity
value and a current computer graphic image opacity channel value
becomes the new current computer graphic image opacity channel
value.
5. A method as claimed in claim 2 wherein said computer graphic
image further comprises a footprint channel which is set when each
pixel is composited and said opacity channel is only composited
with the computer graphic image opacity channel when said footprint
channel is not set.
6. A method as claimed in claim 1 wherein said computer graphic
image comprises a brushing buffer which is subsequently combined
with a second computer graphic image so as to form a final computer
graphics image.
Description
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable.
FIELD OF THE INVENTION
The present invention relates to digital image processing and in
particular discloses The Utilising of Brush Stroking Techniques in
the Generation of Computer Images.
Further the present invention relates to the creation of digital
images and in particular relates to brush stroking techniques
utilised in the creation of digital images.
BACKGROUND OF THE INVENTION
Packages, such as Adobe's Photoshop (Trade Mark) allow for the
creation of complex images through the manipulation of many
different parts or structures in an image to produce a final
overall image. In particular, these packages normally provide for
complex paint brushing techniques or filters. The implementation
details of these paint brushing techniques being well known and
being set out in the standard computer graphics texts. Familiarity
with such techniques is hereinafter assumed.
Known techniques include utilising a paint brush having a
predetermined degree of transparency or, in the alternative,
opacity. In particular, the utilisation of brushing techniques to
achieve water color like effects are provided within the
aforementioned package. Unfortunately, when utilising such brushing
techniques, often imperfections are produced particularly when a
paint brush rounds tight comers or loops on itself. Additionally,
there is general need for effective and efficient brushing
techniques in the field of computer graphics.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide for alternative
forms of brushing so as to produce useful effects.
In accordance with the first aspect of the present invention there
is provided a method of brushing a simulated brush stroke along a
path in a computer graphics image the method comprising the steps
of converting the path to a series of corresponding line segments;
determining a current convex brush edge of said path; determining a
series of substantially equally spaced points along said convex
edge; determining corresponding parametric points along the path;
and utilising the parametric points to place brush template
structures in said computer graphics image.
In a first refinement, the opacity channel is combined such that
the maximum of a current brush template opacity value and a current
computer graphic image opacity channel value becomes the new
current computer graphic image opacity channel value. In a second
refinement, the opacity channel is combined such that the minimum
of a current brush template opacity value and a current computer
graphic image opacity channel value becomes the new current
computer graphic image opacity channel value. In a third
refinement, the computer graphic image further comprises a
footprint channel which is set when each pixel is composited and
said opacity channel is only composited with the computer graphic
image opacity channel when said footprint channel is not set.
BRIEF DESCRIPTION OF THE DRAWINGS
Notwithstanding any other forms which may fall within the scope of
the present invention, preferred forms of the invention will now be
described, by way of example only, with reference to the
accompanying drawings in which:
FIG. 1 illustrates a flow chart of the steps in the preferred
embodiment in compositing brush strokes;
FIG. 2 illustrates the process conversion of Bezier curves to
piecewise line segments;
FIG. 3 illustrates the brush stroking process; and
FIG. 4 illustrates suitable brush stamps for use by the preferred
embodiment.
DESCRIPTION OF PREFERRED AND OTHER EMBODIMENTS
Turning now to FIG. 1, there is illustrated the steps of the
preferred embodiment. It is assumed that the brush stroke is
defined as a piecewise Bezier curve as is standard practice. The
brush stroke is further assumed to have a predetermined thickness.
The stroke is made up of a series of Bezier curves. The first step
11 is to process each piecewise Bezier curve. Each Bezier curve is
first converted to a corresponding piecewise linear curve 12
utilising standard techniques. Next, the "fastest" edge, whose
meaning will become more apparent hereinafter, is utilised to "step
along" the fastest edge in predetermine increments. The positions
are utilised to composite brush strokes 14.
Turning now to FIG. 2, there is illustrated a first Bezier curve 20
which forms the basis of brush stroke 21. The process of converting
the Bezier curve 20 to a corresponding series of line segments eg.
22. The process of linearisation into piecewise linear segments is
standard and well known, being covered in the usual texts. As part
of the linearisation process, the normals eg. 24 at each of the
line end points are also determined. The normals can be determined
from the lines adjoining a point eg. 25 by means of interpolation
between the line gradients if necessary.
Turning now to FIG. 3, there is shown an enlarged view of two line
segments eg. 30, 31. For each point eg. 32 the normals eg. 33, 34
are projected out on each side to a distance of the brush stroking
width. The point 36 having projected normals 37, 38. Next, the
distance 39 is measured between normals 33, 37 and the distance 40
is measured between the normal 34, 38. A "fastest" edge is defined
to be the side having the greatest distance in the sense that a
body travelling along the edge 39 would have to travel
substantially faster than along the edge 40. Hence, the fastest
edge will be the convex edge of a curve.
The fastest edge is utilised to define a predetermined number of
points which are parametrically spaced apart by equal amounts. The
example of FIG. 3 showing three points eg. 43-45 which defined
equally spaced intervals "in distance" along the line 39. The
number of intervals being substantially greater than that
illustrated in FIG. 3.
Next, a corresponding parametric position of each of the points is
determined and is utilised to determine corresponding parametric
points along the line 30. The corresponding locations being
positions where brush strokes are to be placed.
Turning now to FIG. 4, there is illustrated a series of brush
stamps 46, 47, 48. The two stamps 46, 48 being utilised for the end
portions of a line and the portion 47 being continually utilised
along the middle portion of a line.
The brush stamp is defined by three separate channels being a
matte
channel, a bump map channel and a footprint channel. The in the
particular example of FIG. 4, the matte channel of the brush is
illustrated. In the first technique, known as the "max" technique
the matte and bump map channel are utilised to build a brush stroke
in a separate brushing buffer. In this compositing technique, a
brush is built up by taking the maximum opacity ie, the opacity is
replaced with a new opacity when the new opacity exceeds the old
opacity presently in the buffer. The results produced are similar
to the Photoshop air brushing or painting.
In a second compositing technique, hereinafter known as the
"footprint" technique. The footprint channel is utilised such that
the matte value is changed only if a previous brush stamp for a
current line has not written to the brush buffer for that pixel. In
the third technique, again the matte and the bump map channel are
utilised but this time the minimum of the matte channel and the
background, provided the minimum is below an absolute minimum is
utilised.
The above techniques were found to give good results, especially in
the simulation of water color effects.
The following code segment illustrates the line following process
of the preferred embodiment:
______________________________________ /* * $RCSfile:
G2PolylineNav2.h$ * * G2.sub.-- PolylineNavigator2 template class
definition. * * Author: Paul Lapstun, 1996/11/7 * Copyright
Silverbrook Research 1996. * * $Log$ */ #ifndef .sub.--
G2PolylineNav2.sub.-- h.sub.-- #define .sub.--
G2PolylineNav2.sub.-- h.sub.-- #include <bool.h> #include
<G2Polyline.h> #include <G2VectorList.h>
template<class T> class G2.sub.-- PolylineNavigator2 public:
G2.sub.-- PolylineNavigator2(G2.sub.-- Polyline<T> const&
p1, G2.sub.-- VectorList<T> const& t1, G2.sub.-- Real
halfWidth) : m.sub.-- polyline(p1), m.sub.-- tanList(t1), m.sub.--
halfWidth(halfWidth) { Start ( ); } bool AtEnd( ) const { return
m.sub.-- pi == m.sub.-- polyline.end( ); } bool Empty( ) const {
return m.sub.-- polyline.empty( ): } void Start( ); void Advance(T
s); G2.sub.-- Point<T> Point( ) const; G2.sub.--
Vector<T> Tangent( ) const; private: void
SetEffectiveSegmentLength( ); private: G2.sub.-- Polyline<T>
const& m.sub.-- polyline; // polyline being navigated G2.sub.--
VectorList<T> const& m.sub.-- tanList; // tangent list
being navigated G2.sub.-- Real m.sub.-- halfWidth;// half `brush`
width G2.sub.-- Polyline<T>::const.sub.-- iterator m.sub.--
pi; // polyline iterator G2.sub.--
VectorList<T>::const.sub.-- iterator m.sub.-- ti; // tangent
list iterator G2.sub.-- Point<T> m.sub.-- p0; // point at
atart of segment G2.sub.-- point<T> m.sub.-- p1; // point at
end of segment G2.sub.-- Vector<T> m.sub.-- v0; // tangent at
start of segment G2.sub.-- Vector<T> m.sub.-- v1; // tangent
at end of segment G2.sub.-- Vector<T> m.sub.-- n0; // normal
at start of segment G2.sub.-- Vector<T> m.sub.-- n1; //
normal at end of segment T m.sub.-- length; // length of current
segment T m.sub.-- s; // displacement along current segment
G2.sub.-- Real m.sub.-- t; // parameter along current segment };
template<class T> inline void G2.sub.--
PolylineNavigator2<T>::Start( ) { // set iterators to
beginning m.sub.-- pi = m.sub.-- polyline.begin( ); m.sub.-- ti =
m.sub.-- tanList.begin( ); if (AtEnd( )) return; // empty . . . //
get segment start point and tangent m.sub.-- p0 = *m.sub.-- pi++;
m.sub.-- v0 = *m.sub.-- ti++; m.sub.-- n0 = m.sub.-- v0.Normal(
).Normalise( ) * m.sub.-- halfWidth; if (AtEnd( )) return; //
shouldn't happen . . . // get segment end point and tangent
m.sub.-- p1 = *m.sub.-- pi; m.sub.-- v1 = *m.sub.-- ti; m.sub.-- n1
= m.sub.-- v1.Normal( ).Normalise( ) * m.sub.-- halfWidth; // set
effective segment length SetEffectiveSegmentLength( ); // reset
displacement and parameter at start m.sub.-- s = 0; m.sub.-- t = 0;
} template<class T> inline void G2.sub.--
PolylineNavigator2<T>::Advance(T s) { if (AtEnd( )) return;
// skip segments until s falls in current segment while ((m.sub.--
s + s) > m.sub.-- length) { // get segment start point and
tangent m.sub.-- p0 = m.sub.-- p1; m.sub.-- v0 = m.sub.-- v1;
m.sub.-- n0 = m.sub.-- n1; // get segment end point and tangent
m.sub.-- pi++; m.sub.-- ti++; if (AtEnd( )) return; // genuine end
. . . m.sub.-- p1 = *m.sub.-- pi; m.sub.-- v1 = *m.sub.-- ti;
m.sub.-- n1 = m.sub.-- v1.Normal( ).Normalise( ) * m.sub.--
halfWidth; // allow for rest of previous segment s -= (m.sub.--
length - m.sub.-- s); // set effective segment length
SetEffectiveSegmentLength( ); // reset displacement at start of
segment m.sub.-- s = 0; } // move along current segment by
remaining s // and compute parameter at new displacement m.sub.-- s
+= s; m.sub.-- t = m.sub.-- s / m.sub.-- length; }
template<class T> inline G2.sub.-- Point<T> G2.sub.--
PolylineNavigator2<T>::Point( ) const { if (AtEnd( )) return
G2.sub.-- Point<T>(0, 0); return m.sub.--
p0.Interpolate(m.sub.-- p1, m.sub.-- t) ; } template<class T>
inline G2.sub.-- Vector<T> G2.sub.--
PolylineNavigator2<T>::Tangent( ) const { if (AtEnd( ))
return G2.sub.-- Vector<T>(0, 0); G2.sub.-- Vector<T>
tangent = m.sub.-- v0.Interpolate(m.sub.-- v1, m.sub.-- t); return
tangent; } template<class T> inline void G2.sub.--
PolylineNavigator2<T>::SetEffectiveSegmentLength( ) { // the
normals at the end points of the current line // segment have
already been computed and scaled in // length by half the `brush`
width; now construct // vectors which join the ends of the normals;
these // vectors are parallel to the line segment which //
approximates the curve; the vector on the convex // side of the
curve is longer than the line segment; // the vector on the concave
side is shorter; choose // the length of the longer vector for
displacement // stepping; note that a parameter t computed at a //
particular displacement along the chosen vector // can be used
directly to compute the point on the // line segment which
approximates the curve G2.sub.-- Vector<T> vectorA =
(m.sub.-- p1 + m.sub.-- n1) - (m.sub.-- p0 + m.sub.-- n0);
G2.sub.-- Vector<T> vectorB = (m.sub.-- p1 - m.sub.-- n1) -
(m.sub.-- p0 - m.sub.-- n0); G2.sub.-- Real len2A =
vectorA.LengthSquared( ); G2.sub.-- Real len2B =
vectorB.LengthSquared( ); if (len2A > len2B) m.sub.-- length =
sqrt(len2A); else m.sub.-- length = sqrt(len2B); } #endif /*
.sub.-- G2PolylineNav2.sub.-- h.sub.-- */
______________________________________
It would be appreciated by a person skilled in the art that
numerous variations and/or modifications may be made to the present
invention as shown in the specific embodiment without departing
from the spirit or scope of the invention as broadly described. The
present embodiment is, therefore, to be considered in all respects
to be illustrative and not restrictive.
Ink Jet Technologies
The embodiments of the invention use an ink jet printer type
device. Of course many different devices could be used. However
presently popular ink jet printing technologies are unlikely to be
suitable.
The most significant problem with thermal ink jet is power
consumption. This is approximately 100 times that required for high
speed, and stems from the energy-inefficient means of drop
ejection. This involves the rapid boiling of water to produce a
vapor bubble which expels the ink. Water has a very high heat
capacity, and must be superheated in thermal ink jet applications.
This leads to an efficiency of around 0.02%, from electricity input
to drop momentum (and increased surface area) out.
The most significant problem with piezoelectric ink jet is size and
cost. Piezoelectric crystals have a very small deflection at
reasonable drive voltages, and therefore require a large area for
each nozzle. Also, each piezoelectric actuator must be connected to
its drive circuit on a separate substrate. This is not a
significant problem at the current limit of around 300 nozzles per
print head, but is a major impediment to the fabrication of
pagewidth print heads with 19,200 nozzles.
Ideally, the ink jet technologies used meet the stringent
requirements of in-camera digital color printing and other high
quality, high speed, low cost printing applications. To meet the
requirements of digital photography, new ink jet technologies have
been created. The target features include:
low power (less than 10 Watts)
high resolution capability (1,600 dpi or more)
photographic quality output
low manufacturing cost
small size (pagewidth times minimum cross section)
high speed (<2 seconds per page).
All of these features can be met or exceeded by the ink jet systems
described below with differing levels of difficulty. Forty-five
different ink jet technologies have been developed by the Assignee
to give a wide range of choices for high volume manufacture. These
technologies form part of separate applications assigned to the
present Assignee as set out in the list under the heading Cross
References to Related Applications.
The ink jet designs shown here are suitable for a wide range of
digital printing systems, from battery powered one-time use digital
cameras,
through to desktop and network printers, and through to commercial
printing systems
For ease of manufacture using standard process equipment, the print
head is designed to be a monolithic 0.5 micron CMOS chip with MEMS
post processing. For color photographic applications, the print
head is 100 mm long, with a width which depends upon the ink jet
type. The smallest print head designed is covered in US Patent
Application No. 09/112,764, which is 0.35 mm wide, giving a chip
area of 35 square mm. The print heads each contain 19,200 nozzles
plus data and control circuitry.
Ink is supplied to the back of the print head by injection molded
plastic ink channels. The molding requires 50 micron features,
which can be created using a lithographically micromachined insert
in a standard injection molding tool. Ink flows through holes
etched through the wafer to the nozzle chambers fabricated on the
front surface of the wafer. The print head is connected to the
camera circuitry by tape automated bonding.
Tables of Drop-on-Demand Ink Jets
The present invention is useful in the field of digital printing,
in particular, ink jet printing. A number of patent applications in
this field were filed simultaneously and incorporated by cross
reference.
Eleven important characteristics of the fundamental operation of
individual ink jet nozzles have been identified. These
characteristics are largely orthogonal, and so can be elucidated as
an eleven dimensional matrix. Most of the eleven axes of this
matrix include entries developed by the present assignee.
The following tables form the axes of an eleven dimensional table
of ink jet types.
Actuator mechanism (18 types)
Basic operation mode (7 types)
Auxiliary mechanism (8 types)
Actuator amplification or modification method (17 types)
Actuator motion (19 types)
Nozzle refill method (4 types)
Method of restricting back-flow through inlet (10 types)
Nozzle clearing method (9 types)
Nozzle plate construction (9 types)
Drop ejection direction (5 types)
Ink type (7 types)
The complete eleven dimensional table represented by these axes
contains 36.9 billion possible configurations of ink jet nozzle.
While not all of the possible combinations result in a viable ink
jet technology, many million configurations are viable. It is
clearly impractical to elucidate all of the possible
configurations. Instead, certain ink jet types have been
investigated in detail. Forty-five such inkjet types were filed
simultaneously to the present application.
Other ink jet configurations can readily be derived from these
forty-five examples by substituting alternative configurations
along one or more of the 11 axes. Most of the forty-five examples
can be made into ink jet print heads with characteristics superior
to any currently available ink jet technology.
Where there are prior art examples known to the inventor, one or
more of these examples are listed in the examples column of the
tables below. The simultaneously filed patent applications by the
present applicant are listed by USSN numbers. In some cases, a
print technology may be listed more than once in a table, where it
shares characteristics with more than one entry.
Suitable applications for the ink jet technologies include: Home
printers, Office network printers, Short run digital printers,
Commercial print systems, Fabric printers, Pocket printers,
Internet WWW printers, Video printers, Medical imaging, Wide format
printers, Notebook PC printers, Fax machines, Industrial printing
systems, Photocopiers, Photographic minilabs etc.
The information associated with the aforementioned 11 dimensional
matrix are set out in the following tables.
__________________________________________________________________________
ACTUATOR MECHANISM (APPLIED ONLY TO SELECTED INK DROPS) Description
Advantages Disadvantages Examples
__________________________________________________________________________
Thermal An electrothermal heater heats the .diamond-solid. Large
force generated .diamond-solid. High .diamond-solid. Canon
Bubblejet bubble ink to above boiling point, .diamond-solid. Simple
construction .diamond-solid. Ink carrier limited to water 1979 Endo
et al GB transferring significant heat to the .diamond-solid. No
moving parts .diamond-solid. Low efficiency patnet 2,007,162
aqueous ink. A bubble nucleates .diamond-solid. Fast operation
.diamond-solid. High temperatures required .diamond-solid. Xerox
heater-in-pit and quickly forms, expelling the ink. .diamond-solid.
Small chip area required .diamond-solid. High mechanical 1990
Hawkins et al The efficiency of the process is low, for actuator
.diamond-solid. Unusual materials required U.S. Pat. No. with
typically less than 0.05% of the .diamond-solid. Large drive
transistors 4,899,181 electrical energy being transformed
.diamond-solid. Cavitation causes actuator failure .diamond-solid.
Hewlett-Packard into kinetic energy of the drop. .diamond-solid.
Kogation reduces bubble formation TIJ 1982 Vaught et
.diamond-solid. Large print heads are difficult to al U.S. Pat. No.
fabricate 4,490,728 Piezoelectric A piezoelectric crystal such as
lead .diamond-solid. Low power consumption .diamond-solid. Very
large area required for actuator .diamond-solid. Kyser et al U.S.
lanthanum zirconate (PZT) is .diamond-solid. Many ink types can be
.diamond-solid. Difficult to integrate with electronics Pat. No.
3,946,398 electrically activated, and either .diamond-solid. Fast
operation .diamond-solid. High voltage drive transistors
.diamond-solid. Zoltan U.S. Pat. expands, shears, or bends to apply
.diamond-solid. High efficiency No. 3,683,212 pressure to the ink,
ejecting drops. .diamond-solid. Full pagewidth print heads
.diamond-solid. 1973 Stemme U.S. impractical Pat. No. 3,747,120 due
to actuator size .diamond-solid. Epson Stylus .diamond-solid.
Requires electrical poling in high .diamond-solid. Tektronix field
strengths during .diamond-solid. IJ04 Electro- An electric field is
used to activate .diamond-solid. Low power consumption
.diamond-solid. Low maximum strain (approx. 0.01%) .diamond-solid.
Seiko Epson, Usui strictive electrostriction in relaxor materials
.diamond-solid. Many ink types can be .diamond-solid. Large area
required for actuator due to et al JP 253401/96 such as lead
lanthanum zirconate .diamond-solid. Low thermal expansion low
strain .diamond-solid. IJ04 titanate (PLZT) or lead magnesium
.diamond-solid. Electric field strength .diamond-solid. Response
speed is marginal (.about.10 .mu.s) niobate (PMN). required
(approx. 3.5 .diamond-solid. High voltage drive transistors
required V/.mu.m) can be generated .diamond-solid. Full pagewidth
print heads impractical without difficulty due to actuator size
.diamond-solid. Does not require electrical poling Ferroelectric An
electric field is used to induce a .diamond-solid. Low power
consumption .diamond-solid. Difficult to integrate with electronis
.diamond-solid. IJ04 phase transition between the .diamond-solid.
Many ink types can be .diamond-solid. Unusual materials such as
PLZSnT antiferroelectric (AFE) and .diamond-solid. Fast operation
(<1 are required ferroelectric (FE) phase. Perovskite
.diamond-solid. Relatively high longitudinal .diamond-solid.
Actuators require a large area materials such as tin modified lead
strain lanthanum zirconate titanate .diamond-solid. High efficiency
(PLZSnT) exhibit large strains of up .diamond-solid. Electric field
strength of to 1% associated with the AFE to FE around 3 V/.mu.m
can be phase transition. readily provided Electrostatic Conductive
plates are separated by a .diamond-solid. Low power consumption
.diamond-solid. Difficult to operate electrostatic .diamond-solid.
IJ02, IJ04 plates compressible or fluid dielectric .diamond-solid.
Many ink types can be devices in an aqueous environment (usually
air). Upon application of a .diamond-solid. Fast operation
.diamond-solid. The electrostatic acutator will voltage, the plates
attract each other normally need to be separated from and displace
ink, causing drop the ink ejection. The conductive plates may
.diamond-solid. Very large area required to achieve be in a comb or
honeycomb high forces structure, or stacked to increase the
.diamond-solid. High voltage drive transistors may be surface area
and therefore the force. required .diamond-solid. Full pagewidth
print heads are not competitive due to actuator size Electrostatic
A strong electric field is applied to .diamond-solid. Low current
consumption .diamond-solid. High voltage .diamond-solid. 1989 Saito
et al, pull on ink the ink, whereupon electrostatic .diamond-solid.
Low temperature .diamond-solid. May be damaged by sparks due to air
U.S. Pat. No. attraction accelerates the ink towards breakdown
4,799,068 the print medium. .diamond-solid. Requires field strength
increases as .diamond-solid. 1989 Miura et al, the drop size
decreases U.S. Pat. No. .diamond-solid. High voltage drive
transistors required 4,810,954 .diamond-solid. Electrostatic
field
attracts dust .diamond-solid. Tone-jet Permanent An electromagnet
directly attracts a .diamond-solid. Low power consumption
.diamond-solid. Complex .diamond-solid. IJ07, IJ10 magnet permanent
magnet, displacing ink .diamond-solid. Many ink types can be
.diamond-solid. Permanent magnetic materials such as electro- and
cuasing drop ejection. Rare earth .diamond-solid. Fast operation
Neodymium Iron Boride (NdFeB) magnetic magnets with a field
strength around .diamond-solid. High efficiency required. 1 Tesla
can be used. Examples are: .diamond-solid. Easy extension from
.diamond-solid. High local currents required Samarium Cobalt (SaCo)
and nozzles to pagewidth print .diamond-solid. Copper metalization
should be used magnetic materials in the heads for long
electromigration lifetime neodymium iron boron family and low
resistivity (NdFeB, NdDyFeBNb, NdDyFeB, .diamond-solid. Pigmented
inks are usually infeasible etc) .diamond-solid. Operating
temperature limited to the Curie temperature (around 540 K) Soft A
solenoid induced a magnetic field .diamond-solid. Low power
consumption .diamond-solid. Complex .diamond-solid. IJ01, IJ05,
IJ08, magnetic in a soft magnetic core or yoke .diamond-solid. Many
ink types can be .diamond-solid. Materials not usually present in a
IJ10 core electro- fabricated from a ferrous material
.diamond-solid. Fast operation CMOS fab such as NiFe, CoNiFe,
.diamond-solid. IJ12, IJ14, IJ15, magnetic such as electroplated
iron alloys such .diamond-solid. High efficiency CoFe are required
IJ17 as CoNiFe [1], CoFe, or NiFe alloys. .diamond-solid. Easy
extension from .diamond-solid. High local currents required
Typically, the soft magnetic material nozzles to pagewidth print
.diamond-solid. Copper metalization should be used is in two parts,
which are normally heads for long electromigration lifetime held
apart by a spring. When the and low resistivity solenoid is
actuated, the two parts .diamond-solid. Electroplating is required
attract, displacing the ink. .diamond-solid. High saturation flux
density is required (2.0-2.1 T is achievable with CoNiFe [1])
Magnetic The Lorenz force acting on a current .diamond-solid. Low
power consumption .diamond-solid. Force acts as a twisting motion
.diamond-solid. IJ06, IJ11, IJ13, Lorenz carrying wire in a
magnetic field is .diamond-solid. Many ink types can be
.diamond-solid. Typically, only a quarter of the IJ16 force
utilized. .diamond-solid. Fast operation solenoid length provides
force in a This allows the magnetic field to be .diamond-solid.
High efficiency useful direction supplied externally to the print
head, .diamond-solid. Easy extension from .diamond-solid. High
local currents required for example with rare earth nozzles to
pagewidth print .diamond-solid. Copper metalization should be used
permanent magnets. heads for long electromigration lifetime Only
the current carrying wire need and low resistivity be fabricated on
the print-head, .diamond-solid. Pigmented inks are usually
infeasible simplifying materials requirements. Magneto- The
actuator uses the giant .diamond-solid. Many ink types can be
.diamond-solid. Force acts as a twisting motion .diamond-solid.
Fischenbeck, U.S. striction magnetostrictive effect of materials
.diamond-solid. Fast operation .diamond-solid. Unusual materials
such as Terfenol-D Pat. No. 4,032,929 such as Terfenol-D (an alloy
of .diamond-solid. Easy extension from are required .diamond-solid.
IJ25 terbium, dysprosium and iron nozzles to pagewidth print
.diamond-solid. High local currents required developed at the Naval
Ordnance heads .diamond-solid. Copper metalization should be used
Laboratory, hence Ter-Fe-NOL). For .diamond-solid. High force is
available for long electromigration lifetime best efficiency, the
actuator should and low resistivity be pre-stressed to approx. 8
MPa. .diamond-solid. Pre-stressing may be required Surface Ink
under positive pressure is held in .diamond-solid. Low power
consumption .diamond-solid. Requires supplementary force to
.diamond-solid. Silverbrook, EP tension a nozzle by surface
tension. The .diamond-solid. Simple construction effect drop
separation 0771 658 A2 and reduction surface tension of the ink is
reduced .diamond-solid. No unusual materials .diamond-solid.
Requires special ink surfactants related patent below the bubble
threshold, causing required in fabrication .diamond-solid. Speed
may be limited by surfactant applications the ink to egress from
the nozzle. .diamond-solid. High efficiency properties
.diamond-solid. Easy extension from single nozzles to pagewidth
print heads Viscosity The ink viscosity is locally reduced
.diamond-solid. Simple construction .diamond-solid. Requires
supplementary force to .diamond-solid. Silverbrook, EP reduction to
select which drops are to be .diamond-solid. No unusual materials
effect drop separation 0771 658 A2 and ejected. A viscosity
reduction can be required in fabrication .diamond-solid. Requires
special ink viscosity related patent achieved electrothermally with
most .diamond-solid. Easy extension from properties application
inks, but special inks can be nozzles to pagewidth print
.diamond-solid. High speed is difficult to achieve engineered for a
100:1 viscosity heads .diamond-solid. Requires oscillating ink
pressure reduction. .diamond-solid. A high temperature difference
(typically 80 degrees) is required Acoustic An acoustic wave is
generated and .diamond-solid. Can operate without .diamond-solid.
Complex drive circuitry .diamond-solid. 1993 Hadimioglu et focussed
upon the drop ejection nozzle plate .diamond-solid. Complex al, EUP
550,192 region. .diamond-solid. Low efficiency .diamond-solid. 1993
Elrod et al, .diamond-solid. Poor control of drop position EUP
572,230 .diamond-solid. Poor control of drop volume Thermo- An
actuator which relies upon .diamond-solid. Low power consumption
.diamond-solid. Efficient aqueous operation requires a
.diamond-solid. IJ03, IJ09, IJ17, elastic bend differential thermal
expansion upon .diamond-solid. Many ink types can be thermal
insulator on the hot IJ18 actuator Joule heating is used.
.diamond-solid. Simple planar fabrication .diamond-solid. Corrosion
prevention can be difficult .diamond-solid. IJ19, IJ20, IJ21,
.diamond-solid. Small chip area required .diamond-solid. Pigmented
inks may be infeasible, as IJ22 for each actuator pigment particles
may jam the .diamond-solid. IJ23, IJ24, IJ27, .diamond-solid. Fast
operation actuator IJ28 .diamond-solid. High efficiency
.diamond-solid. IJ29, IJ30, IJ31, .diamond-solid. CMOS compatible
voltages IJ32 and currents .diamond-solid. IJ33, IJ34, IJ35,
.diamond-solid. Standard MEMS processes IJ36 can be used
.diamond-solid. IJ37, IJ38, IJ39, .diamond-solid. Easy extension
from IJ40e nozzles to pagewidth print .diamond-solid.
IJ41 heads High CTE A material with a very high .diamond-solid.
High force can be .diamond-solid. Requires special material (e.g.
PTFE) .diamond-solid. IJ09, IJ17, IJ18, thermo- coefficient of
thermal expansion generated .diamond-solid. Requires a PTFE
deposition process, IJ20 elastic (CTE) such as .diamond-solid. PTFE
is a candidate which is not yet standard in .diamond-solid. IJ21,
IJ22, IJ23, acutator polytetrafluoroethylene (PTFE) is low
dielectric constant fabs IJ24 used. As high CTE materials are
insulation in ULSI .diamond-solid. PTFE deposition cannot be
followed .diamond-solid. IJ27, IJ28, IJ29, usually non-conductive,
a heater .diamond-solid. Very low power with high temperature IJ30e
fabricated from a conductive consumption 350.degree. C.) processing
.diamond-solid. IJ31, IJ42, IJ43, material is incorporated. A 50
.mu.m .diamond-solid. Many ink types can .diamond-solid. Pigmented
inks may be infeasible, as IJ44 long PTFE bend actuator with used
pigment particles may jam the bend polysilicon heater and 15 mW
power .diamond-solid. Simple planar fabrication actuator input can
provide 180 .mu.N force and .diamond-solid. Small chip area
required 10 .mu.m deflection. Actuator motions for each actuator
include: .diamond-solid. Fast operation Bend .diamond-solid. High
efficiency Push .diamond-solid. CMOS compatible voltages Buckle
voltages and currents Rotate .diamond-solid. Easy extension from
single nozzles to pagewidth print heads Conductive A polymer with a
high coefficient of .diamond-solid. High force can be
.diamond-solid. Requires special materials .diamond-solid. IJ24
polymer thermal expansion (such as PTFE) is generated development
(High CTE conductive thermo- doped with conducting substances to
.diamond-solid. Very low power polymer) elastic increase its
conductivity to about 3 consumption .diamond-solid. Requires a PTFE
deposition process, actuator orders of magnitude below that of
.diamond-solid. Many ink types can which is not yet standard in
ULSI copper. The conducting polymer used fabs expands when
resistively heated. .diamond-solid. Simple planar fabrication
.diamond-solid. PTFE deposition cannot be followed Examples of
conducting dopants .diamond-solid. Small chip area required with
high temperature (above include: for each actuator 350.degree. C.)
processing 1) Carbon nanotubes .diamond-solid. Fast operation
.diamond-solid. Evaporation and CVD deposition 2) Metal fibers
.diamond-solid. High efficiency techniques cannot be used 3)
Conductive polymers such as .diamond-solid. CMOS compatible
voltages .diamond-solid. Pigmented inks may be feasible, as doped
polythiophene and currents pigment particles may jam the bend 4)
Carbon granules .diamond-solid. Easy extension from actuator
nozzles to pagewidth print heads Shape A shape memory alloy such as
TiNi .diamond-solid. High force is available .diamond-solid.
Fatigue limits maximum number of .diamond-solid. IJ26 memory (also
known as Nitinol - Nickel (stresses of hundreds of cycles alloy
Titanium alloy developed at the MPa) .diamond-solid. Low strain
(1%) is required to extend Naval Ordnance Laboratory) is
.diamond-solid. Large strain is available fatigue resistance
thermally switched between its weak (more than 3%) .diamond-solid.
Cycle rate limited by heat removal martensitic state and its high
.diamond-solid. High corrosion resistance .diamond-solid. Requires
unusual materials (TiNi) stiffness austenic state. The shape of
.diamond-solid. Simple construction .diamond-solid. The latent heat
of transformation the actuator in its martensitic state is
.diamond-solid. Easy extension from must be provided deformed
relative to the austenic nozzles to pagewdith print .diamond-solid.
High current operation shape. The shape change causes heads
.diamond-solid. Requires pre-stressing to distort the ejection of a
drop. .diamond-solid. Low voltage operation martensitic state
Linear Linear magnetic actuators include .diamond-solid. Linear
Magnetic actuators .diamond-solid. Requires unusual semiconductor
.diamond-solid. IJ12 Magnetic the Linear Induction Actuator (LIA),
can be constructed with materials such as soft magnetic alloys
Actuator Linear Permanent Magnet high thrust, long travel, and
(e.g. CoNiFe [1]) Synchronous Actuator (LPMSA), high efficiency
using planar .diamond-solid. Some varieties also require permanent
Linear Reluctance Synchronous semiconductor fabrication magnetic
materials such as Actuator (LRSA), Linear Switched techniques
Neodymium iron boron (NdFeB) Reluctance Actuator (LSRA), and
.diamond-solid. Long actuator travel .diamond-solid. Requires
complex multi-phase drive the Linear Stepper Actuator (LSA).
available circuitry .diamond-solid. Medium force is available
.diamond-solid. High current operation .diamond-solid. Low voltage
operation
__________________________________________________________________________
__________________________________________________________________________
BASIC OPERATION MODE Description Advantages Disadvantages Examples
__________________________________________________________________________
Actuator This is the simplest mode of .diamond-solid. Simple
operation .diamond-solid. Drop repetition rate is usually limited
.diamond-solid. Thermal inkjet directly operation: the actuator
directly .diamond-solid. No external fields to less than 10 KHz.
However, this .diamond-solid. Piezoelectric inkjet pushes ink
supplies sufficient kinetic energy to .diamond-solid. Satellite
drops can not fundamental to the method, but .diamond-solid. IJ01,
IJ02, IJ03, IJ04 expel the drop. The drop must have a avoided if
drop velocity is related to the refill method .diamond-solid. IJ05,
IJ06, IJ07, IJ09 sufficient velocity to overcome the less than 4
m/s used .diamond-solid. IJ11, IJ12, IJ14, IJ16 surface tension.
.diamond-solid. Can be efficient, .diamond-solid. All of the drop
kinetic energy must .diamond-solid. IJ20, IJ22, IJ23, IJ24 upon the
actuator used be provided by the actuator .diamond-solid. IJ25,
IJ26, IJ27, IJ28 .diamond-solid. Satellite drops usually form if
drop .diamond-solid. IJ29, IJ30, IJ31, IJ32 velocity is greater
than 4.5 .diamond-solid. IJ33, IJ34, IJ35, IJ36 .diamond-solid.
IJ37, IJ38, IJ39, IJ40 .diamond-solid. IJ41, IJ42, IJ43, IJ44
Proximity The drops to be printed are selected .diamond-solid. Very
simple print .diamond-solid. Requires close proximity between the
.diamond-solid. Silverbrook, EP by some manner (e.g. thermally
fabrication can be used print head and the print media 0771 658 A2
and induced surface tension reduction of .diamond-solid. The drop
selection transfer roller related patent pressurized ink). Selected
drops are does not need to provide .diamond-solid. May require two
print heads printing applications separated from the ink in the
nozzle
the energy required to alternate rows of the image by contact with
the print medium or separate the drop from the .diamond-solid.
Monolithic color print heads are a transfer roller. nozzle
difficult Electrostatic The drops to be printed are selected
.diamond-solid. Very simple print .diamond-solid. Requires very
high electrostatic field .diamond-solid. Silverbrook, EP pull on
ink by some manner (e.g. thermally fabricaton can be used
.diamond-solid. Electrostatic field for small nozzle 0771 658 A2
and induced surface tension reduction of .diamond-solid. The drop
selection sizes is above air breakdown related patent pressurized
ink). Selected drops are does not need to provide .diamond-solid.
Electrostatic field may attract dust applications separated from
the ink in the nozzle the energy required to .diamond-solid.
Tone-Jet by a strong electric field. separate the drop from the
nozzle Magnetic The drops to be printed are selected
.diamond-solid. Very simple print .diamond-solid. Requires magnetic
.diamond-solid. Silverbrook, EP pull on ink by some manner (e.g.
thermally fabrication can be used .diamond-solid. Ink colors other
than black are 0771 658 A2 and induced surface tension reduction of
.diamond-solid. The drop selection difficult related patent
pressurized ink). Selected drops are does not need to provide
.diamond-solid. Requires very high magnetic fields applications
separated from the ink in the nozzle the energy required to by a
strong magnetic field acting on separate the drop from the the
magnetic ink. nozzle Shutter The actuator moves a shutter to
.diamond-solid. High speed (>50 KHz) .diamond-solid. Moving
parts are required .diamond-solid. IJ13, IJ17, IJ21 block ink flow
to the nozzle. The ink operation can be achieved .diamond-solid.
Requires ink pressure modulator pressure is pulsed at a multiple of
the due to reduced refill time .diamond-solid. Friction and wear
must be considered drop ejection frequency. .diamond-solid. Drop
timing cay be .diamond-solid. Stiction is possible accurate
.diamond-solid. The actuator energy can be very low Shuttered The
actuator moves a shutter to .diamond-solid. Actuators wil small
.diamond-solid. Moving parts are required .diamond-solid. IJ08,
IJ15, IJ18, IJ19 grill block ink flow through a grill to the can be
used .diamond-solid. Requires ink pressure modulator nozzle. The
shutter movement need .diamond-solid. Actuators with small
.diamond-solid. Friction and wear must be considered only be equal
to the width of the grill can be used .diamond-solid. Stiction is
possible holes. .diamond-solid. High speed (>50 KHz) operation
can be achieved Pulsed A pulsed magnetic field attracts an
.diamond-solid. Extremely low energy .diamond-solid. Requires an
external pulsed magnetic .diamond-solid. IJ10 magnetic `ink pusher`
at the drop ejection operation is possible field pull on ink
frequency. An actuator controls a .diamond-solid. No heat
dissipation .diamond-solid. Requires special materials for both
pusher catch, which prevents the ink pusher problems the actuator
and the ink pusher from moving when a drop is not to
.diamond-solid. Complex construction be ejected.
__________________________________________________________________________
__________________________________________________________________________
AUXILIARY MECHANISM (APPLIED TO ALL NOZZLES) Description Advantages
Disadvantages Examples
__________________________________________________________________________
None The actuator directly fires the ink .diamond-solid. Simplicity
of construction .diamond-solid. Drop ejection energy must be
.diamond-solid. Most inkjets, drop, and there is no external field
or .diamond-solid. Simplicity of operation supplied by individual
nozzle actuator including other mechanism required. .diamond-solid.
Small physical size piezoelectric and thermal bubble.
.diamond-solid. IJ01-IJ07, IJ09, IJ11 .diamond-solid. IJ12, IJ14,
IJ20, IJ22 .diamond-solid. IJ23-IJ45 Oscillating The ink pressure
oscillates, .diamond-solid. Oscillating ink pressure
.diamond-solid. Requires external ink pressure .diamond-solid.
Silverbrook, EP ink pressure providing much of the drop ejection
provide a refill pulse, oscillator 0771 658 A2 and (including
energy. The actuator selects which allowing higher operating
.diamond-solid. Ink pressure phase and amplitude related patent
acoustic drops are to be fired by selectively speed must be
carefully controlled applications stimulation) blocking or enabling
nozzles. The .diamond-solid. The actuators may .diamond-solid.
Acoustic reflections in the ink .diamond-solid. IJ08, IJ13, IJ15,
IJ17 ink pressure oscillation may be with much lower energy chamber
must be designed .diamond-solid. IJ18, IJ19, IJ21 achieved by
vibrating the print head, .diamond-solid. Acoustic lenses can be
used or preferably by an actuator in the to focus the sound on the
ink supply. nozzles Media The print head is placed in close
.diamond-solid. Low power .diamond-solid. Precision assembly
required .diamond-solid. Silverbrook, EP proximity proximity to the
print medium. .diamond-solid. High accuracy .diamond-solid. Paper
fibers may cause problems 0771 658 A2 and Selected drops protrude
from the .diamond-solid. Simple print head .diamond-solid. Cannot
print on rough substrates related patent print head further than
unselected construction applications drops, and contact the print
medium. The drop soaks into the medium fast enough to cause drop
separation. Transfer Drops are printed to a transfer roller
.diamond-solid. High accuracy .diamond-solid. Bulky .diamond-solid.
Silverbrook, EP roller instead of straight to the print
.diamond-solid. Wide range of print .diamond-solid. Expensive 0771
658 A2 and medium. A transfer roller can also be substrates can be
used .diamond-solid. Complex related patent used for proximity drop
separation. .diamond-solid. Ink can be dried on applications
transfer roller .diamond-solid. Tektronix hot melt piezeoelectric
inkjet .diamond-solid. Any of the IJ series Electrostatic An
electric field is used to accelerate .diamond-solid. Low power
.diamond-solid. Field strength required for separation
.diamond-solid. Silverbrook, EP selected drops towards the print
.diamond-solid. Simple print head of small drops is near or above
0771 658 A2 and medium. construction breakdown related patent
applications .diamond-solid. Tone-Jet Direct A magnetic field is
used to accelerate .diamond-solid. Low power .diamond-solid.
Requires magnetic .diamond-solid. Silverbrook, EP magnetic selected
drops of magnetic ink .diamond-solid. Simple print head
.diamond-solid. Requires strong magnetic field 0771 658 A2 and
field towards the print medium. construction related patent
applications Cross The print head is placed in a constant
.diamond-solid. Does not require magnetic .diamond-solid. Requires
external
magnet .diamond-solid. IJ06, IJ16 magnetic magnetic field. The
Lorenz force in a materials to be integrated in .diamond-solid.
Current densities may be high, field current carrying wire is used
to move the print head resulting in electromigration the actuator.
manufacturing process problems Pulsed A pulsed magnetic field is
used to .diamond-solid. Very low power operation .diamond-solid.
Complex print head construction .diamond-solid. IJ10 magnetic
cyclically attract a paddle, which is possible .diamond-solid.
Magnetic matierals required in print field pushes on the ink. A
small actuator .diamond-solid. Small print head size head moves a
catch, which selectively prevents the paddle from moving.
__________________________________________________________________________
__________________________________________________________________________
ACTUATOR AMPLIFICATION OR MODIFICATION METHOD Description
Advantages Disadvantages Examples
__________________________________________________________________________
None No actuator mechanical .diamond-solid. Operational simplicity
.diamond-solid. Many actuator mechanisms have .diamond-solid.
Thermal Bubble amplification is used. The actuator insufficient
travel, or Inkjetcient directly drives the drop ejection force, to
efficiently drive the .diamond-solid. IJ01, IJ02, IJ06, process.
ejection process IJ07 Differential An acutator material expands
more .diamond-solid. Provides greater travel in .diamond-solid.
High stresses are involved .diamond-solid. IJ16, IJ25, IJ26
expansion on one side than on the other. The reduced print head
area .diamond-solid. Care must be taken that the materials
.diamond-solid. Piezoelectric bend expansion may be thermal,
.diamond-solid. The bend actuator do not delaminate .diamond-solid.
IJ03, IJ09, IJ17- actuator piezoelectric, magnetostrictive, or a
high force low travel .diamond-solid. Residual bend resulting from
high IJ24 other mechanism. actuator mechanism to high temperature
or high stress .diamond-solid. IJ27, IJ29-IJ39, travel, lower force
formation .diamond-solid. IJ42, IJ43, IJ44 mechanism. Transient A
trilayer bend actuator where the .diamond-solid. Very good
temperature .diamond-solid. High stresses are involved
.diamond-solid. IJ40, IJ41 bend two outside layers are identical.
This stability .diamond-solid. Care must be taken that the
materials actuator cancels bend due to ambient .diamond-solid. High
speed, as a new do not delaminate temperature and reesidual stress.
The can be fired before heat actuator only responds to transient
dissipates heating of one side or the other. .diamond-solid.
Cancels residual stress of formation Reverse The actuator loads a
spring. When .diamond-solid. Better coupling to the .diamond-solid.
Fabrication complexity .diamond-solid. IJ05, IJ11 spring the
actuator is turned off, the spring .diamond-solid. High stress in
the spring releases. This can reverse the force/distance curve of
the actuator to make it compatible with the force/time requirements
of the drop ejection. Actuator A series of thin actuators are
stacked. .diamond-solid. Increased travel .diamond-solid. Increased
fabrication complexity .diamond-solid. Some piezoelectric stack
This can be appropriate where .diamond-solid. Reduced drive voltage
.diamond-solid. Increased possibility of short circuits ink jets
actuators require high electric field due to pinholes
.diamond-solid. IJ04 strength, such as electrostatic and
piezoelectric actuators. Multiple Multiple smaller actuators are
used .diamond-solid. Increase the force .diamond-solid. Actuator
forces may not add linearly, .diamond-solid. IJ12, IJ13, IJ18,
actuators simultaneously to move the ink. from an actuator reducing
efficiency IJ20 Each actuator need provide only a .diamond-solid.
Multiple actuators can .diamond-solid. IJ22, IJ28, IJ42, portion of
the force required. positioned to control ink IJ43 flow accurately
Linear A linear spring is used to transform a .diamond-solid.
Matches low travel .diamond-solid. Requires print head area for the
.diamond-solid. IJ15 Spring motion with small travel and high
spring with higher travel force into a longer travel, lower force
requirements motion. .diamond-solid. Non-contact method of motion
transformation Coiled A bend actuator is coiled to provide
.diamond-solid. Increases travel .diamond-solid. Generally
restricted to .diamond-solid. IJ17, IJ21, IJ34, actuator greater
travel in a reduced chip area. .diamond-solid. Reduces chip area
planar implementations due IJ35 .diamond-solid. Planar
implementations extreme fabrication difficulty in other relatively
easy to fabricate. orientations. Flexure bend A bend actuator has a
small region .diamond-solid. Simple means of increasing
.diamond-solid. Care must be taken not to exceed the
.diamond-solid. IJ10, IJ19, IJ33 actuator near the fixture point,
which flexes travel of a bend actuator elastic limit in the flexure
area much more readily than the .diamond-solid. Stress distribution
is very uneven remainder of the actuator. The .diamond-solid.
Difficult to accurately model with actuator flexing is effectively
finite element analysis converted from an even coiling to an
angular bend, resulting in greater travel of the actuator tip.
Catch The actuator controls a small catch. .diamond-solid. Very low
actuator .diamond-solid. Complex .diamond-solid. IJ10 The catch
either enables or disables .diamond-solid. Very small actuator
.diamond-solid. Requires external force movement of an ink pusher
that is .diamond-solid. Unsuitable for pigmented inks controlled in
a bulk manner. Gears Gears can be used to increase travel
.diamond-solid. Low force, low travel .diamond-solid. Moving parts
are required .diamond-solid. IJ13 at the expense of duration.
Circular actuators can be used .diamond-solid. Several actuator
cycles are required gears, rack and pinion, ratchets, and
.diamond-solid. Can be fabricated .diamond-solid. More complex
drive electronics other gearing methods can be used. standard
surface MEMS .diamond-solid. Complex construction processes
.diamond-solid. Friction, friction, and wear are possible Buckle
plate A buckle plate can be used to change .diamond-solid. Very
fast movement .diamond-solid. Must stay within elastic limits of
the .diamond-solid. S. HIrata et al, "An a slow actuator into a
fast motion. It achievable materials for long device Ink-jet Head .
. .", can also convert a high force, low .diamond-solid. High
stresses involved Proc. IEEE MEMS, travel actuator into a high
travel, .diamond-solid. Generally high power requirement Feb. 1996,
pp 418- medium force motion. 423. .diamond-solid. IJ18, IJ27
Tapered
A tapered magnetic pole can increase .diamond-solid. Linearizes the
magnetic .diamond-solid. Complex .diamond-solid. IJ14 magnetic
travel at the expense of force. force/distance curve pole Lever A
lever and fulcrum is used to .diamond-solid. Matches low travel
.diamond-solid. High stress around the fulcrum .diamond-solid.
IJ32, IJ36, IJ37 transform a motion with small travel with higher
travel and high force into a motion with requirements longer travel
and lower force. The .diamond-solid. Fulcrum are has no linear
lever can also reverse the direction of movement, and can be used
travel. for a fluid seal Rotary The actuator is connected to a
rotary .diamond-solid. High mechanical advantage .diamond-solid.
Complex .diamond-solid. IJ28 impeller impeller. A small angular
deflection .diamond-solid. The ratio of force to .diamond-solid.
Unsuitable for pigmented inks of the actuator results in a rotation
of of the actuator can be the impeller vanes, which push the
matched to the nozzle ink against stationary vanes and out
requirements by varying the of the nozzle. number of impeller vanes
Acoustic A refractive or diffractive (e.g. zone .diamond-solid. No
moving parts .diamond-solid. Large area .diamond-solid. 1993
Hadimioglu et lens plate) acoustic lens is used to .diamond-solid.
Only relevant for acoustic ink jets al, EUP 550,192 concentrate
sound waves. .diamond-solid. 1993 Elrod et al, EUP 572,220 Sharp A
sharp point is used to concentrate .diamond-solid. Simple
construction .diamond-solid. Difficult to fabricate using standard
.diamond-solid. Tone-jet conductive an electrostatic field. VLSI
processes for a surface ejecting point ink-jet .diamond-solid. Only
relevant for electrostatic ink jets
__________________________________________________________________________
__________________________________________________________________________
ACTUATOR MOTION Description Advantages Disadvantages Examples
__________________________________________________________________________
Volume The volume of the actuator changes, .diamond-solid. Simple
constuction in .diamond-solid. High energy is typically required to
.diamond-solid. Hewlett-Packard expansion pushing the ink in all
directions. case of thermal ink jet achieve volume expansion. This
Thermal Inkjet to thermal stress, cavitation, .diamond-solid. Canon
Bubblejet kogation in thermal ink jet implementations Linear, The
actuator moves in a direction .diamond-solid. Efficient coupling to
.diamond-solid. High fabrication complexity may be .diamond-solid.
IJ01, IJ02, IJ04, normal to normal to the print head surface. The
drops ejected normal to the required to achieve IJ07ndicular chip
surface nozzle is typically in the line of surface motion
.diamond-solid. IJ11, IJ14 movement. Parallel to The actuator moves
parallel to the .diamond-solid. Suitable for planar .diamond-solid.
Fabrication .diamond-solid. IJ12, IJ13, IJ15, chip surface print
head surface. Drop ejection fabrication .diamond-solid. Friction
IJ33, may still be normal to the surface. .diamond-solid. Stiction
.diamond-solid. IJ34, IJ35, IJ36 Membrane An actuator with a high
force but .diamond-solid. The effective area of .diamond-solid.
Fabrication .diamond-solid. 1982 Howkins U.S. push small area is
used to push a stiff actuator becomes the .diamond-solid. Actuator
Pat. No. 4,459,601 membrane that is in contact with the membrane
area .diamond-solid. Difficulty of integration in a VLSI ink.
process Rotary The actuator causes the rotation of .diamond-solid.
Rotary levers may be .diamond-solid. Device .diamond-solid. IJ05,
IJ08, IJ13, some element, such a grill or to increase travel
.diamond-solid. May have friction at a pivot point IJ28 impeller
.diamond-solid. Small chip area requirements Bend The actuator
bends when energized. .diamond-solid. A very small change
.diamond-solid. Requires the actuator to be made from
.diamond-solid. 1970 Kyser et al This may be due to differential
dimensions can be at least two distinct layers, or to have U.S.
Pat. thermal expansion, piezoelectric converted to a large motion.
a thermal difference across No. 3,946,398 expansion,
magnetostriction, or other actuator .diamond-solid. IJ03, IJ09,
IJ10, form of relative dimensional change. IJ19 .diamond-solid.
IJ23, IJ24, IJ25, IJ29 .diamond-solid. IJ30, IJ31, IJ33, IJ34
.diamond-solid. IJ35 Swivel The actuator swivel around a central
.diamond-solid. Allows operation where .diamond-solid. Inefficient
coupling to the ink motion .diamond-solid. IJ06 pivot. This motion
is suitable where net linear force on the there are opposite forces
applied to paddle is zero opposite sides of the paddle, e.g.
.diamond-solid. Small chip area Lorenz force. requirements
Straighten The actuator is normally bent, and .diamond-solid. Can
be used with shape .diamond-solid. Requires careful balance of
stresses to .diamond-solid. IJ26, IJ32 straightens when energized.
memory allows where the ensure that the quiescent bend is austenic
phase is planar accurate Double The actuator bends in one direction
.diamond-solid. One actuator can be used .diamond-solid. Difficult
to make the drops ejected by .diamond-solid. IJ36, IJ37, IJ38 bend
when one element is energized, and power two nozzles. both bend
directions identical. bends the other way when another
.diamond-solid. Reduced chip size. .diamond-solid. A small
efficiency loss compared to element is energized. .diamond-solid.
Not sensitive to ambient equivalent single bend actuators.
temperature Shear Energizing the actuator causes a .diamond-solid.
Can increase the effective .diamond-solid. Not readily applicable
to other .diamond-solid. 1985 Fishbeck shear motion in the actuator
material. actuator travel of piezo- mechanisms U.S. Pat. electric
actuators No. 4,584,590 Radial The actuator squeezes an ink
.diamond-solid. Relatively easy to .diamond-solid. High force
.diamond-solid. 1970 Zoltan U.S. constriction reservoir, forcing
ink from a single nozzles from glass .diamond-solid. Inefficient
Pat. No. 3,683,212 constricted nozzle. tubing as macroscopic
.diamond-solid. Difficult to integrate with VLSI structures
processes Coil/uncoil A coiled actuator uncoils or coils
.diamond-solid. Easy to fabricate as .diamond-solid. Difficult to
fabricate for non-planar .diamond-solid. IJ17, IJ21, IJ34, more
tightly. The motion of the free planar VLSI process devices IJ35
end of the actuator ejects the ink. .diamond-solid. Small area
required, .diamond-solid. Poor out-of-plane stiffness therefore low
cost
Bow The actuator bows (or buckles) in the .diamond-solid. Can
increase the speed .diamond-solid. Maximum travel is constrained
.diamond-solid. IJ16, IJ18, IJ27 middle when energized. travel
.diamond-solid. High force required .diamond-solid. Mechanically
rigid Push-Pull Two actuators control a shutter. One
.diamond-solid. The structure is pinned .diamond-solid. Not readily
suitable for inkjets which .diamond-solid. IJ18 actuator pulls the
shutter, and the both ends, so has a high directly push the ink
other pushes it. out-of-plane rigidity Curl inwards A set of
actuators curl inwards to .diamond-solid. Good fluid flow to
.diamond-solid. Design .diamond-solid. IJ20, IJ42 reduce the volume
of ink that they region behind the actuator enclose. increases
efficiency Curl A set of actuators curl outwards, .diamond-solid.
Relatively simple .diamond-solid. Relatively large chip are
.diamond-solid. IJ22 outwards pressurizing ink in a chamber
construction surrounding the actuators, and expelling ink from a
nozzle in the chamber. Iris Multiple vanes enclose a volume of
.diamond-solid. High efficiency .diamond-solid. High fabrication
complexity .diamond-solid. IJ22 ink. These simultabeously rotate,
.diamond-solid. Small chip area .diamond-solid. Not suitable for
pigmented inks reducing the volume between the vanes. Acoustic The
actuator vibrates at a high .diamond-solid. The actuator can be
.diamond-solid. Large area required for efficient .diamond-solid.
1993 Hadimioglu et vibration frequency. physically distant from the
operation at useful et al, EUP 550,192 ink .diamond-solid. Acoustic
coupling and crosstalk .diamond-solid. 1993 Elrod et al,
.diamond-solid. Complex drive circuitry EUP 572,220 .diamond-solid.
Poor control of drop volume and position None In various ink jet
designs the actuator .diamond-solid. No moving parts
.diamond-solid. Various other tradeoffs are required
.diamond-solid. Silverbrook, EP does not move. eliminate moving
parts 0771 648 A2 and related patent applications .diamond-solid.
Tone-jet
__________________________________________________________________________
__________________________________________________________________________
NOZZLE REFILL METHOD Description Advantages Disadvantages Examples
__________________________________________________________________________
Surface After the actuator is energized, it .diamond-solid.
Fabrication simplicity .diamond-solid. Low .diamond-solid. Thermal
inkjet tension typically returns rapidly to its normal
.diamond-solid. Operational simplicity .diamond-solid. Surface
tension force relatively .diamond-solid. Piezoelectric inkjet
position. This rapid return sucks in small compared to actuator
.diamond-solid. IJ01-IJ07, IJ10-IJ14 air through the nozzle
opening. The .diamond-solid. Long refill time usually dominates
.diamond-solid. IJ16, IJ20, IJ22-IJ45 ink surface tension at the
nozzle then the total repetition rate exerts a small force
restoring the meniscus to a minimum area. Shuttered Ink to the
nozzle chamber is .diamond-solid. High speed .diamond-solid.
Requires common ink pressure .diamond-solid. IJ08, IJ13, IJ15, IJ17
oscillating provided at a pressure that oscillates .diamond-solid.
Low actuator energy, as oscillator .diamond-solid. IJ18, IJ19, IJ21
ink pressure at twice the drop ejection frequency. actuator need
only open or .diamond-solid. May not be suitable for pigmented When
a drop is to be ejected, the close the shutter, instead of inks
shutter is opened for 3 half cycles: ejecting the ink drop drop
ejection, actuator return, and refill. Refill After the main
actuator has ejected a .diamond-solid. High speed, as the nozzle
.diamond-solid. Requires two independent .diamond-solid. IJ09
actuator drop a second (refill) actuator is actively refilled
actuators per nozzle energized. The refill actuator pushes ink into
the nozzle chamber. The refill actuator returns slowly, to prevent
its return from emptying the chamber again. Positive The ink is
held a slight positive .diamond-solid. High refill rate, therefore
.diamond-solid. Surface spill must be prevented .diamond-solid.
Silverbrook, EP 0771 ink pressure pressure. After the ink drop is
high drop repetition rate is .diamond-solid. Highly hydrophobic
print head 658 A2 and related ejected, the nozzle chamber fills
possible surfaces are required patent applications quickly as
surface tension and ink .diamond-solid. Alternative for: pressure
both operate to refill the .diamond-solid. IJ01-IJ07, IJ10-IJ14
nozzle. .diamond-solid. IJ16, IJ20,
__________________________________________________________________________
IJ22-IJ45
__________________________________________________________________________
METHOD OF RESTRICTING BACK-FLOW THROUGH INLET Description
Advantages Disadvantages Examples
__________________________________________________________________________
Long inlet The ink inlet channel to the nozzle .diamond-solid.
Design simplicity .diamond-solid. Restricts refill .diamond-solid.
Thermal inkjet channel chamber is made long and relatively
.diamond-solid. Operational simplicity .diamond-solid. May result
in a relatively large .diamond-solid. Piezoelectric inkjet narrow,
relying on viscous drag to .diamond-solid. Reduces crosstalk chip
area .diamond-solid. IJ42, IJ43 reduce inlet back-flow.
.diamond-solid. Only partially effective Positive The ink is under
a positive pressure, .diamond-solid. Drop selection and
.diamond-solid. Requires a method (such as a .diamond-solid.
Silverbrook, EP 0771 ink pressure so that in the quiescent state
some of separation forces can be nozzle rim or effective 658 A2 and
related the ink drop already protrudes from reduced hydrophobizing,
or both) patent applications the nozzle. .diamond-solid. Fast
refill time prevent flooding of the .diamond-solid. Possible
operation This reduces the pressure in the surface of the print of
the following: nozzle chamber which is required to .diamond-solid.
IJ01-IJ07, IJ09-IJ12 eject a certain volume of ink. The
.diamond-solid. IJ14, IJ16, IJ20, IJ22, reduction in chamber
pressure results .diamond-solid. IJ23-IJ34, IJ36-IJ41 in a
reduction in ink pushed out .diamond-solid. IJ44 through the inlet.
Baffle One or more baffles are placed in the .diamond-solid. The
refill rate is not .diamond-solid. Design .diamond-solid. HP
Thermal Ink Jet inlet ink flow. When the actuator is restricted as
the long inlet .diamond-solid. May increase fabrication
.diamond-solid. Tektronix energized, the rapid ink movement method.
complexity (e.g. Tektronix piezoelectric ink jet creates eddies
which restrict the flow .diamond-solid. Reduces crosstalk melt
Piezoelectric print heads). through the inlet. The slower refill
process is unrestricted, and does not result in eddies. Flexible
flap In this method recently discloed by .diamond-solid.
Significantly reduces .diamond-solid. Not applicable to most inkjet
.diamond-solid. Canon restricts Canon, the expanding actuator flow
for edge-shooter configurations
inlet (bubble) pushes on a flexible flap thermal ink jet devices
.diamond-solid. Increased fabrication complexity that restricts the
inlet. .diamond-solid. Inelastic deformation of polymer flap
results in creep over extended use Inlet filter A filter is located
between the ink .diamond-solid. Additional advantage of
.diamond-solid. Restricts refill .diamond-solid. IJ04, IJ12, IJ24,
IJ27 inlet and the nozzle chamber. The filtration .diamond-solid.
May result in complex construction .diamond-solid. IJ29, IJ30
filter has a multitude of small holes .diamond-solid. Ink filter
may be fabricated or slots, restricting ink flow. The with no
additional process filter also removes particles which steps may
block the nozzle. Small inlet The ink inlet channel to the nozzle
.diamond-solid. Design simplicity .diamond-solid. Restricts refill
.diamond-solid. IJ02, IJ37, IJ44 compared to chamber has a
substantially smaller .diamond-solid. May result in a relatively
large chip nozzle cross section than that of the nozzle, area
resulting in easier ink egress out of .diamond-solid. Only
partially effective the nozzle than out of the inlet. Inlet shutter
A secondary actuator controls the .diamond-solid. Increases speed
of the .diamond-solid. Requires separate refill actuator and
.diamond-solid. IJ09 position of a shutter, closing off the jet
print head operation drive circuit ink inlet when the main actuator
is energized. The inlet is The method avoids the problem of
.diamond-solid. Back-flow problem .diamond-solid. Requires careful
design to minimize .diamond-solid. IJ01, IJ03, IJ05, IJ06 located
inlet back-flow by arranging the ink- eliminated the negative
pressure behind .diamond-solid. IJ07, IJ10, IJ11, IJ14 behind
pushing surface of the actuator paddle .diamond-solid. IJ16, IJ22,
IJ23, IJ25 the ink- between the inlet and the nozzle.
.diamond-solid. IJ28, IJ31, IJ32, IJ33 pushing .diamond-solid.
IJ34, IJ35, IJ36, IJ39 surface .diamond-solid. IJ 40, IJ41 Part of
the The actuator and a wall of the ink .diamond-solid. Significant
reductions .diamond-solid. Small increase in fabrication
.diamond-solid. IJ07, IJ20, IJ26, IJ38 actuator chamber are
arranged so that the back-flow can be achieved complexity moves to
motion of the actuator closes off the .diamond-solid. Compact
designs possible shut off the inlet. inlet Nozzle In some
configurations of ink jet, .diamond-solid. Ink back-flow problem
.diamond-solid. None related to ink back-flow on .diamond-solid.
Silverbrook, EP 0771 actuator does there is no expansion or
movement eliminated actuation 658 A2 and related not result in of
an actuator which may cause ink patent applications ink back-
back-flow through the inlet. .diamond-solid. Valve-jet flow
.diamond-solid. Tone-jet .diamond-solid. IJ08, IJ13, IJ15, IJ17
.diamond-solid. IJ18, IJ19,
__________________________________________________________________________
IJ21
__________________________________________________________________________
NOZZLE CLEARING METHOD Description Advantages Disadvantages
Examples
__________________________________________________________________________
Normal All of the nozzles are fired .diamond-solid. No added
complexity on .diamond-solid. May not be sufficient to displace
.diamond-solid. Most ink jet systems nozzle periodically, before
the ink has a print head ink .diamond-solid. IJ01-IJ07, IJ09-IJ12
firing chance to dry. When not in use the .diamond-solid. IJ14,
IJ16, IJ20, IJ22 nozzles are sealed (capped) against
.diamond-solid. IJ23-IJ34, IJ36-IJ45 air. The nozzle firing is
usually performed during a special clearing cycle, after first
moving the print head to a cleaning station. Extra power In systems
which heat the ink, but do .diamond-solid. Can be highly effective
.diamond-solid. Requires higher drive voltage for .diamond-solid.
Silverbrook, EP 0771 to ink heater not boil it under normal
situations, the heat is adjacent to the clearing 658 A2 and related
nozzle clearing can be achieved by nozzle .diamond-solid. May
require larger drive transistors patent applications over-powering
the heater and boiling ink at the nozzle. Rapid The actuator is
fired in rapid .diamond-solid. Does not require extra
.diamond-solid. Effectiveness depends substantially .diamond-solid.
May be used with: succession succession. In some configurations,
circuits on the the print head upon the configuration of the
.diamond-solid. IJ01-IJ07, IJ09-IJ11 of actuator this may cause
heat build-up at the .diamond-solid. Can be readily controlled
nozzle .diamond-solid. IJ14, IJ16, IJ20, IJ22 pulses nozzle which
boils the ink, clearing and initiated by digital logic
.diamond-solid. IJ23-IJ25, IJ27-IJ34 the nozzle. In other
situations, it may .diamond-solid. IJ36-IJ45 cause sufficient
vibrations to dislodge clogged nozzles. Extra power Where an
actuator is not normally .diamond-solid. A simple solution
.diamond-solid. Not suitable where there is a hard .diamond-solid.
May be used with: to ink driven to the limit of its motion,
applicable limit to actuator movement .diamond-solid. IJ03, IJ09,
IJ16, IJ20 pushing nozzle clearing may be assisted by
.diamond-solid. IJ23, IJ24, IJ25, IJ27 actuator providing an
enhanced drive signal .diamond-solid. IJ29, IJ30, IJ31, IJ32 to the
actuator. .diamond-solid. IJ39, IJ40, IJ41, IJ42 .diamond-solid.
IJ43, IJ44, IJ45 Acoustic An ultransonic wave is applied to the
.diamond-solid. A high nozzle clearing .diamond-solid. High
implementation cost if .diamond-solid. IJ08, IJ13, IJ15, IJ17
resonance ink chamber. The wave is of an capability can be achieved
system does not already include .diamond-solid. IJ18, IJ19, IJ21
appropriate amplitude and frequency .diamond-solid. May be
implemented acoustic actuator to cause sufficient force at the
nozzle very low cost in systems to clear blockages. This is easiest
to which already include achieve if the ultrasonic wave is at a
acoustic actuators resonant frequency of the ink cavity. Nozzle A
microfabricated plate is pushed .diamond-solid. Can clear severely
.diamond-solid. Accurate mechanical alignment is .diamond-solid.
Silverbrook, EP 0771 clearing against the nozzles. The plate has a
nozzles required 658 A2 and related plate post for every nozzle.
The array of .diamond-solid. Moving parts are required patent
applications posts .diamond-solid. There is risk of damage to the
nozzles .diamond-solid. Accurate fabrication is required Ink
pressure The pressure of the ink is .diamond-solid. May be
effective where .diamond-solid. Requries pressure pump or other
.diamond-solid. May be used with all pulse temporarily increased so
that ink other methods cannot be pressure actuator IJ series ink
jets streams from all of the nozzles. This used .diamond-solid.
Expensive
may be used in conjunction with .diamond-solid. Wasteful of ink
actuator energizing. Print head A flexible `blade` is wiped across
the .diamond-solid. Effective for planar .diamond-solid. Difficult
to use if print head .diamond-solid. Many ink jet systems wiper
print head surface. The blade is head surfaces surface is
non-planar or very usually fabricated from a flexible
.diamond-solid. Low cost fragile polymer, e.g. rubber or synthetic
.diamond-solid. Requires mechanical parts elastomer.
.diamond-solid. Blade can wear out in high volume print systems
Separate ink A separate heater is provided at the .diamond-solid.
Can be effective where .diamond-solid. Fabrication complexity
.diamond-solid. Can be used with boiling nozzle although the normal
drop e- other nozzle clearing many IJ series ink heater ection
mechanism does not require it. methods cannot be used jets The
heaters do not require individual .diamond-solid. Can be
implemetned at no drive circuits, as many nozzles can additional
cost in some be cleared simultaneously, and no inkjet
configurations imaging is required.
__________________________________________________________________________
__________________________________________________________________________
NOZZLE PLATE CONSTRUCTION Description Advantages Disadvantages
Examples
__________________________________________________________________________
Electro- A nozzle plate is separately .diamond-solid. Fabrication
simplicity .diamond-solid. High temperature and pressures are
.diamond-solid. Hewlett Packard formed fabricated from
electroformed nickel, required to bond nozzle plate nickel and
bonded to the print head chip. .diamond-solid. Minimum thickness
constraints .diamond-solid. Differential thermal expansion Laser
ablated Individual nozzle holes are ablated .diamond-solid. No
masks required .diamond-solid. Each hole must be individually
.diamond-solid. Canon Bubblejet or drilled by an intense UV laser
in a nozzle .diamond-solid. Can be quite fast formed
.diamond-solid. 1988 Sercel et al., polymer plate, which is
typically a polymer .diamond-solid. Some control over
.diamond-solid. Special equipment required SPIE, Vol. 998 such as
polyimide or polysulphone profile is possible .diamond-solid. Slow
where there are many Excimer Beam .diamond-solid. Equipment
required thousands of nozzles per print Applications, pp. 76-
relatively low cost .diamond-solid. May produce thin burrs at exit
83 holes .diamond-solid. 1993 Watanabe et al. U.S. Pat No.
5,208,6043 Silicon A separate nozzle plate is .diamond-solid. High
accuracy is attainable .diamond-solid. Two part .diamond-solid. K.
Bean, IEEE micro- micromachined from single crystal .diamond-solid.
High Transactions on machined silicon, and bonded to the print head
.diamond-solid. Requires precision alignment Electron Devices,
wafer. .diamond-solid. Nozzles may be clogged by Vol. ED-25, No.
10, adhesive 1978, pp 1185-1195 .diamond-solid. Xerox 1990 Hawkins
et al., U.S. Pat. No. 4,899,181 Glass Fine glass capillaries are
drawn from .diamond-solid. No expensive equipment .diamond-solid.
Very small nozzle sizes are .diamond-solid. 1970 Zoltan U.S.
capillaries glass tubing. This method has been required difficult
to form Pat. No. 3,683,212 used for making individual nozzles,
.diamond-solid. Simple to make single .diamond-solid. Not suited
for mass production but is difficult to use for bulk nozzles
manufacturing of print heads with thousands of nozzles. Monolithic,
The nozzle plate is deposited as a .diamond-solid. High accuracy
(<1 .diamond-solid. Requires sacrificial layer under the
.diamond-solid. Silverbrook, EP 0771 surface layer using standard
VLSI deposition .diamond-solid. Monolithic nozzle plate to form the
658 A2 and related micro- techniques. Nozzles are etched in the
.diamond-solid. Low cost chamber patent applications machined
nozzles plate using VLSI lithography .diamond-solid. Existing
processes can .diamond-solid. Surface may be fragile to the touch
.diamond-solid. IJ01, IJ02, IJ04, IJ11 using VLSI and etching. used
.diamond-solid. IJ12, IJ17, IJ18, IJ20 lithographic .diamond-solid.
IJ22, IJ24, IJ27, IJ28 processes .diamond-solid. IJ29, IJ30, IJ31,
IJ32 .diamond-solid. IJ33, IJ34, IJ36, IJ37 .diamond-solid. IJ38,
IJ39, IJ40, IJ41 .diamond-solid. IJ42, IJ43, IJ44 Monolithic, The
nozzle plate is a buried etch stop .diamond-solid. High accuracy
(<1 .diamond-solid. Requires long etch times .diamond-solid.
IJ03, IJ05, IJ06, IJ07 etched in the wafer. Nozzle chambers are
.diamond-solid. Monolithic .diamond-solid. Requires a support wafer
.diamond-solid. IJ08, IJ09, IJ10, IJ13 through etched in the front
of the wafer, and .diamond-solid. Low cost .diamond-solid. IJ14,
IJ15, IJ16, IJ19 substrate the wafer is thinned from the back
.diamond-solid. No differential expansion .diamond-solid. IJ21,
IJ23, IJ25, IJ26 sie. Nozzles are then etched in the etch stop
layer. No nozzle Various methods have been tried to .diamond-solid.
No nozzles to become .diamond-solid. Difficult to control drop
position .diamond-solid. Ricoh 1995 Sekiya et plate eliminate the
nozzles entirely, to clogged accurately al U.S. Pat No. prevent
nozzle clogging. These .diamond-solid. Crosstalk 5,412,413 include
thermal bubble mechanisms .diamond-solid. 1993 Hadimioglu et and
acoustic lens mechanisms al EUP 550,192 .diamond-solid. 1993 Elrod
et al EUP 572,220 Trough Each drop ejector has a trough
.diamond-solid. Reduced manufacturing .diamond-solid. Drop firing
direction is sensitive to .diamond-solid. IJ35 through which a
paddle moves. complexity wicking. There is no nozzle plate.
.diamond-solid. Monolithic Nozzle slit The elimination of nozzle
holes and .diamond-solid. No nozzles to become .diamond-solid.
Difficult to control drop position .diamond-solid. 1989 Saito et al
instead of replacement by a slit encompassing clogged accurately
U.S. Pat. No. individual many actuator positions reduces
.diamond-solid. Crosstalk 4,799,068 nozzles nozzle clogging, but
increases .diamond-solid. Crosstalk problems crosstalk due to ink
surface waves
__________________________________________________________________________
__________________________________________________________________________
DROP EJECTION DIRECTION Description Advantages Disadvantages
Examples
__________________________________________________________________________
Edge Ink flow is along the surface of the .diamond-solid. Simple
construction .diamond-solid. Nozzles limited to edge
.diamond-solid. Canon Bubblejet (`edge chip, and ink drops are
ejected from .diamond-solid. No silicon etching .diamond-solid.
High resolution is difficult 1979 Endo et al GB shooter`) the chip
edge. .diamond-solid. Good heat sinking .diamond-solid. Fast color
printing requires one patent 2,007,162 substrate print head per
color
.diamond-solid. Xerox heater-in-pit .diamond-solid. Mechanically
strong 1990 Hawkins et al .diamond-solid. Ease of chip handing U.S.
Pat. No. 4,899,181 .diamond-solid. Tone-jet Surface Ink flow is
along the surface of the .diamond-solid. No bulk silicon etching
.diamond-solid. Maximum ink flow is severely .diamond-solid.
Hewlett-Packard TIJ (`roof chip, and ink drops are ejected from
required restricted 1982 Vaught et al shooter`) the chip surface,
normal to the plane .diamond-solid. Silicon can make an U.S. Pat
No. of the chip. effective heat sink 4,490,728 .diamond-solid.
Mechanical strength .diamond-solid. IJ02, IJ11, IJ12, IJ20
.diamond-solid. IJ22 Through Ink flow is through the chip, and ink
.diamond-solid. High ink flow .diamond-solid. Requires bulk silicon
etching .diamond-solid. Silverbrook, EP 0771 chip, drops are
ejected from the front .diamond-solid. Suitable for pagewidth 658
A2 and related forward surface of the chip. .diamond-solid. High
nozzle packing patent applications (`up density therefore low
.diamond-solid. IJ04, IJ17, IJ18, IJ24 shooter`) manufacturing cost
.diamond-solid. IJ27-IJ45 Through Ink flow is through the chip, and
ink .diamond-solid. High ink flow .diamond-solid. Requries wafer
thinning .diamond-solid. IJ01, IJ03, IJ05, IJ06 chip, drops are
ejected from the rear .diamond-solid. Suitable for pagewidth
.diamond-solid. Requires special handling during .diamond-solid.
IJ07, IJ08, IJ09, IJ10 reverse surface of the chip. .diamond-solid.
High nozzle packing manufacture .diamond-solid. IJ13, IJ14, IJ15,
IJ16 (`down density therefore low .diamond-solid. IJ19, IJ21, IJ23,
IJ25 shooter`) manufacturing cost .diamond-solid. IJ26 Through Ink
flow is through the actuator, .diamond-solid. Suitable for
piezoelectric .diamond-solid. Pagewidth print heads require
.diamond-solid. Epson Stylus actuator which is not fabricated as
part of the print heads several thousand connections
.diamond-solid. Tektronix hot melt same substrate as the drive
drive circuits piezoelectric ink jets transistors. .diamond-solid.
Cannot be manufactured in standard CMOS fabs .diamond-solid.
Complex assembly required
__________________________________________________________________________
__________________________________________________________________________
INK TYPE Description Advantages Disadvantages Examples
__________________________________________________________________________
Aqueous, Water based ink which typically .diamond-solid.
Environmentally friendly .diamond-solid. Slow .diamond-solid. Most
existing inkjets dye contains: water, dye, surfactant,
.diamond-solid. No odor .diamond-solid. Corrosive .diamond-solid.
All IJ series ink jets humectant, and biocide. .diamond-solid.
Bleeds on .diamond-solid. Silverbrook, EP 0771 Modern ink dyes have
high water- .diamond-solid. May 658 A2 and related fastness, light
fastness .diamond-solid. Cockles patent applications Aqueous, Water
based ink which typically .diamond-solid. Environmentally friendly
.diamond-solid. Slow .diamond-solid. IJ02, IJ04, IJ21, IJ26 pigment
contains: water, pigment, surfactant, .diamond-solid. No odor
.diamond-solid. Corrosive .diamond-solid. IJ27, IJ30 humectant, and
biocide. .diamond-solid. Reduced bleed .diamond-solid. Pigment may
clog nozzles .diamond-solid. Silverbrook EP 0771 Pigments have an
advantage in .diamond-solid. Reduced wicking .diamond-solid.
Pigment may clog actuator 658 A2 and related reduced bleed, wicking
and .diamond-solid. Reduced strikethrough mechanisms patent
applications strikethrough. .diamond-solid. Cockles .diamond-solid.
Piezoelectric ink-jets .diamond-solid. Thermal ink jets (with
significant restrictions) Methyl Ethyl MEK is a highly volatile
solvent .diamond-solid. Very fast drying .diamond-solid. Odorous
.diamond-solid. All IJ series ink jets Ketone used for industrial
printing on .diamond-solid. Prints on various .diamond-solid.
Flammable (MEK) difficult surfaces such as aluminum such as metals
and plastics cans. Alcohol Alcohol based inks can be used
.diamond-solid. Fast drying .diamond-solid. Slight .diamond-solid.
All IJ series ink jets (ethanol, 2- where the printer must operate
at .diamond-solid. Operates at sub-freezing .diamond-solid.
Flammable butanol, and temperatures below the freezing temperatures
others) point of water. An example of this is .diamond-solid.
Reduced paper cockle in-camera consumer photographic
.diamond-solid. Low cost printing. Phase The ink is solid at room
temperature. .diamond-solid. No drying time- ink .diamond-solid.
High .diamond-solid. Tektronix hot melt change and is melted in the
print head before instantly freezes on the .diamond-solid. Printed
ink typically has a `waxy` piezoelectric ink jets (hot melt)
jetting. Hot melt inks are usually print medium feel
.diamond-solid. 1989 Nowak U.S. wax based, with a melting piont
.diamond-solid. Almost any print medium .diamond-solid. Printed
pages may `block` Pat. No. 4,820,346 around 80.degree. C. After
jetting the ink can be used .diamond-solid. Ink temperature may be
above the .diamond-solid. All IJ series ink jets freezes almost
instantly upon .diamond-solid. No paper cockle occurs curie point
of permanent magnets contacting the print medium or a
.diamond-solid. No wicking occurs .diamond-solid. Ink heaters
consume power transfer roller. .diamond-solid. No bleed occurs
.diamond-solid. Long warm-up time .diamond-solid. No strikethrough
occurs Oil Oil based inks are extensively used .diamond-solid. High
solubility medium .diamond-solid. High viscosity: this is a
signficant .diamond-solid. All IJ series ink jets in offset
printing. They have some dyes limitation for use in inkjets,
advantages in improved .diamond-solid. Does not cockle paper which
usually require a low characteristics on paper (especially
.diamond-solid. Does not wick through viscosity. Some short chain
and no wicking or cockle). Oil soluble paper multi-branched oils
have a dies and pigments are required. sufficiently low viscosity.
.diamond-solid. Slow drying Micro- A microemulsion is a stable,
self .diamond-solid. Stops ink bleed .diamond-solid. Viscosity
higher than water .diamond-solid. All IJ series ink jets emulsion
forming emulsion of oil, water, and .diamond-solid. High dye
solubility .diamond-solid. Cost is slightly higher than water
surfactant. The characteristic drop .diamond-solid. Water, oil, and
amphiphilic based ink size is less than 100 nm, and is soluble dies
can be used .diamond-solid. High surfactant concentration
determined by the preferred .diamond-solid. Can stabilize pigment
required (around 5%) curvature of the surfactant. suspensions
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